[PATCH v1 0/1] i2c: npcm: Add clock toggle in case of stuck bus during init

[PATCH v1 0/1] i2c: npcm: Add clock toggle in case of stuck bus during init

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

Hi,

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to toggle them first.

Fixes: 76487532f797 (i2c: npcm: Add slave enable/disable function)
Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
---

Tali Perry (1):
  i2c: npcm: Add clock toggle in case of stuck bus during init in
    npcm_i2c_init_module

 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH v1 1/1] i2c: npcm: Add clock toggle in case of stuck bus during init in npcm_i2c_init_module

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 3ad6124be80f..78c85015d955 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2043,10 +2043,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempt recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
+			dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
+			dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return -ENXIO;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.34.1

**Reported-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>**
**Tested-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>**

[PATCH v2 0/1] i2c: npcm: Add clock toggle recovery

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

Hi,

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to toggle them first.

Fixes: 76487532f797 (i2c: npcm: Add slave enable/disable function)
Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
---

Tali Perry (1):
  i2c: npcm: Add clock toggle recovery

 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH v2 1/1] i2c: npcm: Add clock toggle recovery

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 3ad6124be80f..78c85015d955 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2043,10 +2043,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempt recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
+			dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
+			dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return -ENXIO;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.34.1

**Reported-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>**
**Tested-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>**

Re: [PATCH v2 1/1] i2c: npcm: Add clock toggle recovery

[Mukesh Kumar Savaliya]

On 3/25/2025 2:28 AM, mohammed.0.elbadry@gmail.com wrote:
> From: Tali Perry <tali.perry1@gmail.com>
> 
> During init of the bus, the module checks that the bus is idle.
> If one of the lines are stuck try to recover them first before failing.
> Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> 
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
> ---
>   drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 3ad6124be80f..78c85015d955 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -2043,10 +2043,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
>   
>   	/* Check HW is OK: SDA and SCL should be high at this point. */
>   	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> -		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> -		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> -			npcm_i2c_get_SCL(&bus->adap));
> -		return -ENXIO;
> +		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempt recover\n", bus->num,
> +				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> +		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> +			dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> +			dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> +				npcm_i2c_get_SCL(&bus->adap));
Should combine logging into one line. First line you say they are low, 
second line you are printing the actual status, may be conflicting ?
> +			return -ENXIO;
> +		}
>   	}
>   
>   	npcm_i2c_int_enable(bus, true);

[PATCH v3] i2c: npcm: Add clock toggle recovery

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 2fe68615942e..f05cae20cb27 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempt recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
+			dev_err(bus->dev, "I2C%d init fail: lines are low, SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return -ENXIO;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.49.0.472.ge94155a9ec-goog

Re: [PATCH v3] i2c: npcm: Add clock toggle recovery

[Mukesh Kumar Savaliya]

On 3/28/2025 1:08 AM, mohammed.0.elbadry@gmail.com wrote:
> From: Tali Perry <tali.perry1@gmail.com>
> 
> During init of the bus, the module checks that the bus is idle.
> If one of the lines are stuck try to recover them first before failing.
> Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> 
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
> ---
>   drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 2fe68615942e..f05cae20cb27 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
>   
>   	/* Check HW is OK: SDA and SCL should be high at this point. */
>   	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> -		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> -		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> -			npcm_i2c_get_SCL(&bus->adap));
> -		return -ENXIO;
> +		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempt recover\n", bus->num,
> +				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> +		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
You are here post trying recovery. In the log below you may want to add, 
"Post recovery" ? instead of "init fail" ? Just a suggestion.
> +			dev_err(bus->dev, "I2C%d init fail: lines are low, SDA=%d SCL=%d\n",
> +				bus->num, npcm_i2c_get_SDA(&bus->adap),
Thanks for making previous change. Now "lines are low" not relevant as 
you just need to print status 1 or 0.
> +				npcm_i2c_get_SCL(&bus->adap));
> +			return -ENXIO;
> +		}
>   	}
>   
>   	npcm_i2c_int_enable(bus, true);

[PATCH v4] i2c: npcm: Add clock toggle recovery

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 2fe68615942e..caf9aa1e6319 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
+			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return -ENXIO;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.49.0.472.ge94155a9ec-goog

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

[Mukesh Kumar Savaliya]

Looks good to me.

On 3/29/2025 1:02 AM, mohammed.0.elbadry@gmail.com wrote:
> From: Tali Perry <tali.perry1@gmail.com>
> 
> During init of the bus, the module checks that the bus is idle.
> If one of the lines are stuck try to recover them first before failing.
> Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> 
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
> ---
>   drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 2fe68615942e..caf9aa1e6319 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
>   
>   	/* Check HW is OK: SDA and SCL should be high at this point. */
>   	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> -		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> -		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> -			npcm_i2c_get_SCL(&bus->adap));
> -		return -ENXIO;
> +		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
> +				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> +		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> +			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> +				bus->num, npcm_i2c_get_SDA(&bus->adap),
> +				npcm_i2c_get_SCL(&bus->adap));
> +			return -ENXIO;
> +		}
>   	}
>   
>   	npcm_i2c_int_enable(bus, true);

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

[Andi Shyti]

Hi Mohammed,

On Fri, Mar 28, 2025 at 07:32:50PM +0000, mohammed.0.elbadry@gmail.com wrote:
> From: Tali Perry <tali.perry1@gmail.com>
> 
> During init of the bus, the module checks that the bus is idle.
> If one of the lines are stuck try to recover them first before failing.
> Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> 
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
> ---

we are missing the changelog here. You are at v4 and I need to
see the changes between the versions. For now it's OK, please,
next time don't forget to add the changelog.

One more thing, no need to send patches as --in-reply-to your
previous patch.

>  drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 2fe68615942e..caf9aa1e6319 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
>  
>  	/* Check HW is OK: SDA and SCL should be high at this point. */
>  	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> -		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> -		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> -			npcm_i2c_get_SCL(&bus->adap));
> -		return -ENXIO;
> +		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,

the space at the beginning of the line should be removed. I will
take care of it if you won't be asked to send a new version.

> +				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> +		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> +			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> +				bus->num, npcm_i2c_get_SDA(&bus->adap),
> +				npcm_i2c_get_SCL(&bus->adap));
> +			return -ENXIO;

why don't we return the error coming from
npcm_i2c_recovery_tgclk() instead of forcing it to ENXIO?

Thanks,
Andi

> +		}
>  	}
>  
>  	npcm_i2c_int_enable(bus, true);
> -- 
> 2.49.0.472.ge94155a9ec-goog
> 

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

[Mohammed Elbadry]

Hi Andi,

On Sun, Apr 13, 2025 at 4:06 PM Andi Shyti <andi.shyti@kernel.org> wrote:
>
> Hi Mohammed,
>
> On Fri, Mar 28, 2025 at 07:32:50PM +0000, mohammed.0.elbadry@gmail.com wrote:
> > From: Tali Perry <tali.perry1@gmail.com>
> >
> > During init of the bus, the module checks that the bus is idle.
> > If one of the lines are stuck try to recover them first before failing.
> > Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).
> >
> > Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> > Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
> > ---
>
> we are missing the changelog here. You are at v4 and I need to
> see the changes between the versions. For now it's OK, please,
> next time don't forget to add the changelog.
I understand, I will do that, thank you.

>
> One more thing, no need to send patches as --in-reply-to your
> previous patch.
>
> >  drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> > index 2fe68615942e..caf9aa1e6319 100644
> > --- a/drivers/i2c/busses/i2c-npcm7xx.c
> > +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> > @@ -1967,10 +1967,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
> >
> >       /* Check HW is OK: SDA and SCL should be high at this point. */
> >       if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
> > -             dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
> > -             dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
> > -                     npcm_i2c_get_SCL(&bus->adap));
> > -             return -ENXIO;
> > +             dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
>
> the space at the beginning of the line should be removed. I will
> take care of it if you won't be asked to send a new version.
>
Got it, thank you.
> > +                              npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> > +             if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> > +                     dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> > +                             bus->num, npcm_i2c_get_SDA(&bus->adap),
> > +                             npcm_i2c_get_SCL(&bus->adap));
> > +                     return -ENXIO;
>
> why don't we return the error coming from
> npcm_i2c_recovery_tgclk() instead of forcing it to ENXIO?

The error that comes from the current driver is only -ENOTRECOVERABLE.
I do not see why we cannot return that error instead. I understand the
difference between both states; however, from the driver's
perspective, on initialization, ENXIO and ENOTRECOVERABLE behavior is
identical in that state.

ENXIO was what the driver returned by default without trying to
recover. Do you recommend changing it? Let me know. I am happy to send
the v5 patch with the change and address the above comments, too.

Thank you,
Mo
>
> Thanks,
> Andi
>
> > +             }
> >       }
> >
> >       npcm_i2c_int_enable(bus, true);
> > --
> > 2.49.0.472.ge94155a9ec-goog
> >

Re: [PATCH v4] i2c: npcm: Add clock toggle recovery

[Andi Shyti]

Hi Mohammed,

...

> > > +                              npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
> > > +             if (npcm_i2c_recovery_tgclk(&bus->adap)) {
> > > +                     dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
> > > +                             bus->num, npcm_i2c_get_SDA(&bus->adap),
> > > +                             npcm_i2c_get_SCL(&bus->adap));
> > > +                     return -ENXIO;
> >
> > why don't we return the error coming from
> > npcm_i2c_recovery_tgclk() instead of forcing it to ENXIO?
> 
> The error that comes from the current driver is only -ENOTRECOVERABLE.
> I do not see why we cannot return that error instead. I understand the
> difference between both states; however, from the driver's
> perspective, on initialization, ENXIO and ENOTRECOVERABLE behavior is
> identical in that state.

I think it makes more sense to return the error we receive from
npcm_i2c_recovery_tgclk(). Then we can discuss whether that error
is correct or not, but that's a different topic.

> ENXIO was what the driver returned by default without trying to
> recover. Do you recommend changing it? Let me know. I am happy to send
> the v5 patch with the change and address the above comments, too.

Yes, please do.

Andi

[PATCH v5] i2c: npcm: Add clock toggle recovery

[Mohammed Elbadry]

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index de713b5747fe..0757a23dc1cd 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2178,10 +2178,15 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		ret = npcm_i2c_recovery_tgclk(&bus->adap);
+		if (ret) {
+			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return ret;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.39.5 (Apple Git-154)

[PATCH v5] i2c: npcm: Add clock toggle recovery

[Mohammed Elbadry]

From: Tali Perry <tali.perry1@gmail.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@quicinc.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index de713b5747fe..4738fc450a6b 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2178,10 +2178,15 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		ret = npcm_i2c_recovery_tgclk(&bus->adap);
+		if (ret) {
+			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return ret;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.39.5 (Apple Git-154)

Re: [PATCH v2 0/1] i2c: npcm: Add clock toggle recovery

[Mukesh Kumar Savaliya]

On 3/25/2025 2:28 AM, mohammed.0.elbadry@gmail.com wrote:
> From: Tali Perry <tali.perry1@gmail.com>
> 
> Hi,
> 
> During init of the bus, the module checks that the bus is idle.
> If one of the lines are stuck try to toggle them first.
> 
As such there is one file change and single patch. You may go ahead 
without cover-letter. Just my thought.
> Fixes: 76487532f797 (i2c: npcm: Add slave enable/disable function)
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@gmail.com>
> ---
> 
> Tali Perry (1):
>    i2c: npcm: Add clock toggle recovery
> 
>   drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
>   1 file changed, 8 insertions(+), 4 deletions(-)
> 

[PATCH v1 0/1] i2c: npcm: Add clock toggle in case of stuck bus during init

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

Hi,

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to toggle them first.

Fixes: 76487532f797 (i2c: npcm: Add slave enable/disable function)
Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@google.com>
---

Tali Perry (1):
  i2c: npcm: Add clock toggle in case of stuck bus during init in
    npcm_i2c_init_module

 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

-- 
2.34.1

[PATCH v1 1/1] i2c: npcm: Add clock toggle in case of stuck bus during init in npcm_i2c_init_module

[mohammed.0.elbadry]

From: Tali Perry <tali.perry1@gmail.com>

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@google.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 3ad6124be80f..78c85015d955 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2043,10 +2043,14 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempt recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		if (npcm_i2c_recovery_tgclk(&bus->adap)) {
+			dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
+			dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return -ENXIO;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.34.1

**Reported-by: Mohammed Elbadry <mohammed.0.elbadry@google.com>**
**Tested-by: Mohammed Elbadry <mohammed.0.elbadry@google.com>**